LG · Microwave Moderate

F-2 — Thermistor / Temperature Out of Range

F-2 means the control detected a problem with the microwave's thermistor (temperature sensor) — the temperature reading is out of range. This is a temperature-sensing circuit fault, not a stuck or shorted keypad button (that meaning belongs to other brands' F2 code and to LG's own F-3 control-panel code).

Keep using it?
Yes, with caution
DIY difficulty
Moderate
Verified against
lg.com ↗

How to fix it

  1. Unplug the microwave and let it sit at least 5 minutes before opening the cabinet — microwaves store a lethal charge in the HV capacitor even when unplugged. If you're not comfortable working near it, call a technician.
  2. Locate the thermistor (temperature sensor) — position varies by model; check your model's service sheet.
  3. Unplug the thermistor connector and inspect it and the harness for damage, corrosion, or a loose pin.
  4. Test the thermistor's resistance against the spec for your model; replace it if it's open, shorted, or out of range.
  5. Reseat the connector and reassemble. If F-2 returns with a known-good thermistor and harness, the main control board is suspect.

Why it happens

Typical signs: F-2 on display · Microwave may not heat properly, run short cycles, or fail to start a cook cycle · Fault can appear intermittently, especially right after a cook cycle or once the unit has warmed up

  • Failed thermistor The sensor has drifted, gone open, or shorted, so its reading falls outside the range the control expects.
  • Disconnected or damaged thermistor wiring The connector at the thermistor has backed off, or the harness is chafed or pinched.
  • Main control board sensing fault Less common — the board's input circuit can't read a valid signal even from a good thermistor.

Parts you may need

If diagnosis points to a failed part, these are the common replacements. As an Amazon Associate we earn from qualifying purchases.

  • LG microwave thermistor / temperature sensor Common replacement
    Amazon →

More LG microwave codes

DOOR DOOR / Door Error — Door switch / interlock fault F-1 F-1 — Main Control Board Fault F-3 F-3 — Key short / specific button stuck F-4 F-4 — Humidity / steam sensor fault F-5 F-5 — Damper Switch Error F19 F19 — Inverter / High-Voltage Fault

All LG codes → All microwave codes →

Frequently asked questions

What does the F-2 code mean on a LG microwave?

F-2 means the control detected a problem with the microwave's thermistor (temperature sensor) — the temperature reading is out of range. This is a temperature-sensing circuit fault, not a stuck or shorted keypad button (that meaning belongs to other brands' F2 code and to LG's own F-3 control-panel code).

What causes the F-2 code on a LG microwave?

Failed thermistor: The sensor has drifted, gone open, or shorted, so its reading falls outside the range the control expects. Disconnected or damaged thermistor wiring: The connector at the thermistor has backed off, or the harness is chafed or pinched. Main control board sensing fault: Less common — the board's input circuit can't read a valid signal even from a good thermistor.

Is it safe to keep using a LG microwave with a F-2 error?

Yes, with caution. This is rated a moderate-severity fault.

How do I fix F-2 on a LG microwave?

Unplug the microwave and let it sit at least 5 minutes before opening the cabinet — microwaves store a lethal charge in the HV capacitor even when unplugged. If you're not comfortable working near it, call a technician. Locate the thermistor (temperature sensor) — position varies by model; check your model's service sheet. Unplug the thermistor connector and inspect it and the harness for damage, corrosion, or a loose pin.

Always unplug an appliance before servicing it. This guide is for informational purposes and is not a substitute for a qualified technician. Verified against manufacturer documentation: lg.com.